Nutrient Remobilization and C:N:P Stoichiometry in Response to Elevated CO2 and Low Phosphorus Availability in Rice Cultivars Introgressed with and Without Pup1

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The continuously rising atmospheric CO2 concentration potentially increase plant growth through stimulating C metabolism; however, plant C:N:P stoichiometry in response to elevated CO2 (eCO2) under low P stress remains largely unknown. We investigated the combined effect of eCO2 and low phosphorus on growth, yield, C:N:P stoichiometry, and remobilization in rice cv. Kasalath (aus type), IR64 (a mega rice variety), and IR64-Pup1 (Pup1 QTL introgressed IR64). In response to eCO2 and low P, the C accumulation increased significantly (particularly at anthesis stage) while N and P concentration decreased leading to higher C:N and C:P ratios in all plant components (leaf, sheath, stem, and grain) than ambient CO2. The remobilization efficiencies of N and P were also reduced under low P with eCO2 as compared to control conditions. Among cultivars, the combined effect of eCO2 and low P was greater in IR64-Pup1 and produced higher biomass and grain yield as compared to IR64. However, IR64-Pup1 exhibited a lower N but higher P concentration than IR64, indicating that the Pup1 QTL improved P uptake but did not influence N uptake. Our study suggests that the P availability along with eCO2 would alter the C:N:P ratios due to their differential partitioning, thereby affecting growth and yield.
Rice, Phosphorus, Carbon dioxide
Sharma, S., Raviteja, D. H., Kumar, T., Bindraban, P. S., & Pandey, R. (2024). Nutrient remobilization and c:N:P stoichiometry in response to elevated CO2 and low phosphorus availability in rice cultivars introgressed with and without PUP1. Plant Physiology and Biochemistry, 210, 108657.